Ostapenko A. The Increase of Ecological Safety of Paper and Cardboard Production from Auxiliary Raw Materials

The thesis is devoted to the improvement of the technological process of obtaining paper and cardboard from wastepaper through the use of amphoteric polymer resins (APR), which will help to reduce the amount of solid waste, to reduce water consumption and to increase physical and mechanical factors of cardboard and paper products. The characteristics of the fibers of recycled paper and APR, used for the production of paper and cardboard, are determined. It is defined that the process of water absorption of wastepaper consists of three stages: rapid water absorption, slow water absorption and the stage of reaching the saturation limit. It is determined that wastepaper with increasing capacity for water absorption are arranged in the following sequence: wastepaper of MS-8B-3 grade - wastepaper of MS-7B-2 grade - wastepaper of MS-6B-3 grade - wastepaper of MS-5B-2 grade. It is shown that the use of 1H NMR spectra is useful only for qualitative assessment of APR azetidine groups and it is expedient to use 13C NMR spectroscopy to studying the structural and functional features of resin macromolecules. Using 13C NMR spectroscopy, the relative content of azetidine groups in APR various types was calculated and the mechanism of interaction of APR with cellulose macromolecules of auxiliary fibrous intermediates was studied. The regularities of the influence of APR azetidine groups on the physical and mechanical properties of paper and cardboard were determined, taking into account various conditions for the formation of paper and cardboard. It is shown that, depending on the APR type, the content of these groups from theoretically possible varies within a wide range from 7% to 81%. It was determined that Ultrarez 200 with azetidine content of 76% is the most effective APR among the reagents to achieve the quality indicators of cardboard and paper products. The influence of APR on the process of forming paper and cardboard from auxiliary raw materials is studied, depending on the degree of mass and temperature grinding. One of the main factors for increasing the productivity of papermaking machines is the intensification of the process of dewatering of the pulp during the formation of the paper web. It is shown that the use of the investigated APR allows to increase the dewatering rate of the pulp by 1,9-2,4 times with the low reagent costs and a high degree of freeness value of the fiber suspension. Comparative studies showed that the use of APR at low temperatures makes it possible to increase the rate of dehydration without spending additional funds to increase the temperature of the pulp. The influence of APR on the level of tray waters contamination and the weight holding on the grid was studied with the aim of reducing the volumes of liquid waste in the production of paper and cardboard using recycled materials. It was shown that the use of APR reduces the turbidity of the tray water depending on their costs and on the type of these reagents in the fiber suspension composition. It is determined that an increase in the content of azetidine groups in APR at optimal costs contributes to a significant increase in the fiber content on the grid on the PRM up to 98 % using poor quality raw materials, which reduces the loss of the initial fiber material by reducing the volume of solid waste. It is shown that the effectiveness of tray waters lightening in the production of paper and paperboard from recycled materials, which contain a significant amount of fibrous materials, increases with the use of APR. The results on increasing the effectiveness of the mass content on the papermaking machine grid to reduce the intensity of pollution of the tray waters and to reduce the volume of solid waste can be considered positive only if the products obtained meet the existing quality standards. Therefore, the influence of APR on the physical and mechanical properties of corrugated paper and cardboard for flat layers of corrugated cardboard from waste paper of various grades was studied. It was determined that the use of APR binary system ensures the reduction in cost of cardboard from waste paper of MS-5B-2 grade by 3272,7 UAH per tonne due to the replacement of primary raw materials, an increase in the fiber content on the mesh, which leads to decreasing liquid waste and reducing the costs of flocculants for sludge dewatering.